[ern]

The relief second officer basically pulled up when the stall protection had been disabled and by the time the other pilot and captain realized what was happening it was too late to save the plane.

There is a design flaw though: the sidesticks in modern Airbus planes are independent, so the other pilot didn’t get any tactile feedback when the second officer was pulling back.

[berti]

You do get an audible "DUAL INPUT DUAL INPUT" warning and some lights though [1]. It is never allowable to make sidestick inputs unless you are the single designated "pilot flying", but people can sometimes break down under stress of course.

[1] https://safetyfirst.airbus.com/app/themes/mh_newsdesk/docume...